PROJECT SUMMARY Prescription drug-related adverse deaths rank as the fourth-leading cause of death in the United States. Opioid pain relievers constitute the most commonly abused class of drugs, involved in over 66% of all drug overdose deaths in 2016. More people die from overdoses of prescription opioids than from all other drugs combined (including illegal drugs). Fentanyl is the most widely misused prescription opioid. It is often prescribed to treat severe pain but is 40?50 times more potent than heroin and carries a high risk of overdose. In addition to being included as part of the routine drug screening, fentanyl is on the screening panel of the National Safety Council (for workplace screening) and is being increasingly adopted for other federal guidelines, e.g., the Department of Transportation in 2017, to ensure compliance with responsible prescribing practices and patient adherence to opioid therapy. The tests currently used to detect fentanyl, however, are problematic. The initial, ?point of care? tests are often quick and simple, like a dipstick test, but are widely recognized for their lack of specificity and sensitivity. Point of care tests are not great at distinguishing between fentanyl and its derivative compounds and have high false-positive and -negative rates, sometimes as high as 30%. For this reason, the positive results from these initial tests have to undergo a second round of ?confirmatory? testing at larger clinical laboratories via either gas or liquid chromatography-mass spectrometry. This added step is not efficient; it means greater time (sometimes weeks for results), expense, and back log. As reported by the Drug Enforcement Administration?s National Forensic Laboratory Information System (NFLIS), hundreds of thousands of samples are processed each year, and this number is expected to rise. Better, more sensitive, and efficient drug testing capabilities are needed to address the growing national opioid epidemic. In line with this clear need and the objectives of the HEAL initiative, Ceres Nanoscience, Inc. proposes a Phase I SBIR to demonstrate the feasibility of its smart nanoparticle technology (Nanotrap) as a sample concentrator to enable the faster, cheaper, and more discerning detection of fentanyl and its derivatives from large volumes of urine. Supported by promising proof-of-principle data, the specific aims for this initiative are to: Aim 1: demonstrate the feasibility of Nanotrap particles to pre-concentrate and improve the detection of fentanyl and its derivatives from large-volume urine samples; and Aim 2: identify a Nanotrap workflow suitable for sample processing in multiple contexts, i.e., medium-volume reference lab and high-volume confirmatory testing lab workflows. These studies will inform a future Phase II effort aimed at expanding the capabilities of the Nanotrap fentanyl assay and evaluating its placement in real-world drug testing laboratories. Ultimately, if successful, the formulation of Nanotrap particles into a platform that could be used by clinical, commercial, and forensic laboratories for pre-testing sample enrichment of multiple fentanyl derivatives, analogs, or synthetic variants could translate into more comprehensive, efficient testing practices, reduce costs for drug testing, and ultimately help to address the current technical bottlenecks that are only hindering efforts to combat this national epidemic.